Device for use in filling cavities in teeth



8, 1953 H. M. HOLMES 2,648,906

DEVICE FOR USE IN FILLING CAVITIES IN TEETH Filed Jan. 12, 1951" INVENTOR. H/LLflRD M. How/Es BY v zflw mrwbu ATTORNEYS.

Patented Aug. 18, 1953 v yOFFlICE d amasosw- DEVICE FOR .USEIN FHLING'CAVITIES .IN TEETH Hillard MaIItilIiieS, LakeTahoe, Calif.

Application January 12, 1951, 'Seria1 No."20 5,6"71

6 Clai-I'ns.

1 This 'invention relates toia method "of "filling cavities in'teeth and to a device 'for use in filling such cavities.

A recentfil'ling material in dentistry identified in thedental profession as plastic acrylic filling,

being an acrylic plastic that is impervious to any o'f thenatura'l fluids of the mouth and that more nearlyeorrespond to natural tooth color'andcolor texture'than any material heretofore discovered andusedindentistry.

Up tothe present time "a 'large percentage of the fillings of the above-described material placed in the-patients" teeth have proven-to be failures for -the reason that they have 'become leaky or have' locsened entirely from the tooth cavities.

One (if "the-objects of the present invention is the provision of a method of filling cavities with a settingplastic material of the above type or of any type havingth'e same characteristics so that said fillings will not become leaky "or "loosened;

Another object of the invention is the provision eta-device for us'e i-n-ioar'rying out the above-mentioned method.

A 'still further object of the invention is the provision of a method and means for procuring substantially per'fect *marginal adaptation *of the plastic fillingon' all portions of the cavity margin simultaneously;

An additional-object 'is the 'prov'i's'i'on Of means for forcing the setting plastic' fi ing 'materialih a plastic state into everyinii r iute cre v iceand oi'm pressure :dercut' of the cavity under "a u and maintamingarsaia ressure uriti'l the filfin'g materiali'has setp:

.It ishould'zbe mentioned that the use "of acrylic plastic fillin'gunateri'al'ri's "entai s-any in thosecay ities that areiin the: outer-sides or between front teeth iintthe momma-newbie ii'gs when be unsightly or r'obgrectionable to *inost persons if of 'silvermm'algam or gold. In other words,"the

elevational .view of the various elernents of the device for use in filling atooth, atooth being indicated-at the lefthand end (lookingat the drawing) in-which-thecavity to be filled is'showm Fig. 2 is a still lai'gerview "th'an' that or 1 in whieh the device-of Fig. 1 is assembled-and in tooth "filling ='positieii with the filling material sho'v'vniri thecavity-and in the dev-i'ce.

Fig. i; is 'a plan view ofa matrix adapted for use Withthe device shewn'in Fig. =1;

Fig. 4 is plan -of a "slightlydifferent matrix *tha'n' in' Fig. 1, the 's'aime"elements being each matrix, but the filiin-"g element ."ortube of Fig. 4 being at a different angular'fiaosi'tiohralativeto the' niatrix sheet. YT

Figs. 5, 6 are respectivelyedge or side elevatio'nal vie-its of'the' matriees of *Figs. '3 and 4.

Fig. "l' is a front elevationalview of a tooth to be 'fill'e'd illustrating' a matrix *of the type shown Fig; 3; but trimmed and "fitted over the :cavity preparatory to sealing the same to the "tooth.

Fig. 8' is an enlarged fragmentary sectional view 'of'shghtly difieierit shaped filling elements or members respectively on the matrix 'andfilling device thanis shbwn theother figures.

Fig. '9 'a' sec-tiQnal'VieW of a modified form of the invention that is-more c'ompact than the-other devices.

is to be understood that thewdev-ices shown in all of the vi'ews are-greatlyenlarged over their actual sizes, and the :parts shown 'in Fig. -2 are substantially enlarged over that shown in Fig. 1.

In thedrawings (Figs. 1 and .2) ,---the tooth to befilled is-indicated at Panda-cavity 2 iormed therein. For purpose-of explanationof the invention the-same number may be given the-tooth in Fig. "7 that is to be filled, and-the cavity in said tooth is shown beingadjacent to---the next tooth-3. r e v Cav-ity2 may :bezprepared for filling inthe usual manner, having undercutsides to retain the filling material. v v 4 I e in Figs. '3 to 6 inclusive are shown' several matrices, the body of each bGlIIQthG'COIl-VfilltiOIlEl material ofthin readily bendablemetal. Sometimes this metal is slightlytempered .to more readily retain its :bent shape, and at other -.times it is more in the nature of a foil that is easily bent and that has little if any springy characteristic. Such material as is used at the.present time for the same general-purpose is suitable for use.

The matrixof Figs. 3 and 5 is thin sheetmetal body 4 that :is-oblong in shape and centrally apertured with a :fi-l-ling tube 5 secured in the aperture at one end and projecting from said body at right angles .to .the plane of said body.

-I-n the matrix of-Figsh l -and;6,-the body I has a filling tube 8 secured thereto-at anangle less 3 than 90 degrees. Otherwise the two matrices are the same.

The matrix of Figs. 3 and are used where the cavity is so positioned that the tube 5 will be exposed and directed generally toward the center of the opening of the mouth when the matrix is in position, whereas the matrix of Figs. 4 and 6 are used when the cavity is where the tube 8 will be directed generally toward the center of the mouth opening when the mouth of the patient is open. The reason for this is that the filling device that is to be attached to the tubes 5 or 8 (as will later be explained) will project from the tube to which it is attached, and will usually project from the mouth. Hence it is more convenient for both the dentist and the patient if it projects from the mouth without the necessity for uncomfortably distorting the mouth.

The rectangular shape of the matrices shown in Figs. 3 to 6 inclusive is common, inasmuch as this provides ample material for trimming and shaping the matrix around the tooth and over the cavity to be filled. In Fig. '7 the matrix B has been trimmed so that the edges are curved, and the upper edge will extend along or across the gum line. The tube 5 or 8 in any event communicates directly with the open side of the cavity to be filled.

After the body of the matrix has been trimmed and shaped so that it will fit over the cavity to be filled, as explained above, it may be secured in place by use of a sealing wax 6 such as a conventional impression compound. This wax or compound may extend completely over the matrix and the portion of the tooth around the matrix and adheres firmly to the tooth and to the matrix. Obviously it may extend over adjoining teeth in some instances. However, the wax does not absolutely seal off the cavity in a manner preventing escape of air. Usually such escape is possible at the gum line inasmuch as most cavities in the front teeth occur close to such line. If not, a, fractional portion of the matrix at a point along its edge may be left uncovered to permit escape of air from within the cavity.

i The matrix over the cavity is shaped so that the curvature of its inner surface where it extends across the cavity conforms to the normal curvature of that portion of the tooth in which thecavity is located, before such cavity was made. The maintenance of this curvature is quite important, particularly where the filling is between teeth. If it is not maintained, the surface of the filling will not have the normal and proper position relative to the surface of the adjoining tooth that is adjacent thereto, and trouble will develop.

Where the matrix is drawn tightly into engagement with 'the tooth to be filled, as has been the practice heretofore, the matrix usually flattens out slightly where it extends across the cavity. The exterior surface of the filling material takes this flattened form, with the result that it does not have the desired and highly important surface curvature it should have.

With the present invention the matrix is not tensioned, and there is nothing to change its curve. Once the desired curvature is procured, it will stay that way.

Where the cavity is between teeth or nearly so and the matrix must be positioned between the teeth in order to extend over the cavity, it

is customary to wedge the adjoining teeth apart a sufficient distance with a peg to insert the matrix. After the tooth is filled and the wedge or peg is withdrawn, the teeth will come together.

After the matrix is secured in position by the wax or compound, thefilling device may be coupled with the filling tube 5 or 3.

This filling device comprises a cylindrical body I 0 having a head i l at one end thereof. The opposite end is open (Fig. 1). The head I l is apertured for receiving one end of a discharge tube l2 that is secured to said head coaxial with the said aperture therein.

The tube l2 may be counterbored at its outer end as at M to closely receive the filling tube 5, and the diameters of the tubes 5, I2 are the same. Shoulder I5 defining the juncture between the counterbored portion l2 and the bore in the discharge tube may function as a stop for engagement with the outer end of tube 5 so that the bores in said tubes will be smooth and continuous as seen in Fig. 2.

Reciprocably fitted in the open end of the body [0 is a plunger l5. This plunger may project outwardly of the open end of the body [0 and a hollow cap I! receives the outwardly projecting end of the plunger therein. This cap I! has a head [3 closing its outer end, and a helical spring i9 may be within said cap between head It? and the end of the plunger when the cap is over an end of said plunger.

Secured to head I8 by any suitable means, such as a machine screw 20, is a generally U-shaped clip of spring material, generally designated 2|, Legs 22 of clip 2| are of the same length and in substantially opposed relationship for extending longitudinally of the cap at opposite sides there-, of. The closed end of the clip extends across the head 18 of the cap and the screw 29 extends through said closed end.

Said legs 22 are bowed longitudinally with their concavely curved sides facing each other, and their outer end portions at their free ends are turned inwardly toward each other, and slightly rearwardly to provide hooklike elements 23. These elements 23 are adapted to engage a side of an annular outwardly opening recess 2c that extends around the body II! when the filling device is assembled.

Around the open end of cap I! is a radially outwardly projecting flange 25 across which the legs 22 extend. The hooklike elements 23 on the free ends of legs 22 are spaced axially outwardly of the annular flange 25 a distance sufiicient for said elements to engage the side of said recess 24 that is adjacent the cap l1, and to hold spring l9 under suflicient compression to provide the desired pressure on the filling material to be carried in body [0 between the end of plunger I6 and head II as will later be described more in detail;

The plastic material, as has already been stated is an acrylic resin and is indicated at 21 in Fig. 2. This plastic material is placed within the cylindrical body In in a plastic. condition after the body It has been coupled to the filling tube 5 (or 8) of the matrix. 1

Th coupling of the latter to the matrix filling tube usually is done after thematrix is 'secured over the cavity, but in any event the discharge tube [5 of the filling device may then be secured to the matrix generally as indicated in Fig. 2..

The amount of sealing wax or impression compound that is used must be sufficient to firmly hold the matrix in position and to hold the filling device in position coupled to the matrix.

position indicated in Fig. -2 when the-hook or-- catches2 3 Will;automatically snap into the recess or groove 24. 5 I

In the event the plunger fits snugly in cap-11, a vent hole 28 maybe-provided in the cap head to permit quick escape of air. Also a vent 25;

may be made in side of cap ;l0.- After passing vent 26 the speed of'the piston will 'be checked before itreaches the plastic.

It is also to be noted that the hook-like -elements 23 have slanted-generally axially and inwardly, facing surfaces 23 (Fig. 2) that initially engage the free end edges of the ,body it upon axial movement ofcap [1 toward the body ill-to automaticallyspread the legs 22- so that said end elements ,23 will snap into the recess 24 whenthey reach the latter. Q U 1 The amount of plastic material with which the body H} is originally charged shouldbe slightlyin excess c the m untr qu d r th a t and; for in t P seWaYJ Q W n h evit an said body [0, so that thepressure on the plastic material is applied over the full cross sectional a of h b u n settin and. partne isation of theplasticmaterial.

The l ly lar e a ea the .en pfplu se a v o h a ea. of th re eadinsi to the cavity through tube J2 and tothe area .of the t e er w h. t nsi n. vof.::I i. s..!9 i at a un m sustainsdnres ureg about 0 '1bs, .1per squ r millimet r. .cnthefilling terial in the cavity. The pressure may be varied to suit conditions, and may be more or less than the above, but whatever pressure is employed it should. be -suficientato.-.efiect substantially sufiicient compression-. of -t,he-re silientdent-ine of the tooth to compensate for the shrinkage in the acrylic resin during setting of the, latter so, that the filling -will be a tight fit in the cayity after the acrylic resin has set, Normally the aboye pressure o r substantially such pressurcisadequate.

The chancenf unif rm p essur n th acrylic, pl sti. .wi11 result a ub rmlrnens fillin a w l a in rinaa t htandsat sia crr fil n o t minu si tim isade uat f =.-th. plastic material to set, after which p eri, od .-the tube may be severed along line X-X (Fig. 2) and the body in may be replaced by a new one for another filling operation. The wax or compound 6 is readily removed, together with the matrix body 4, after which the surface of the correct curve or contour has been kept on the 1111- ing inasmuch as the curvature of the body I has been correct, and no tension has been placed on said matrix as in a conventional operation where the matrix is drawn against the tooth around the cavity under tension.

To remove the cap ll from the body, it is only necessary to press the legs toward each other at points between flange 25 and the closed end of the clip element, when the hook ends 23 will be caused to spring apart as the legs engage said flange.

During the setting period of the plastic, the fillin device may be left in place coupled to the matrix. It need not be held by any other means than the matrix, being relatively small and light in Weight.

The expendable. port-ions, 11611. .5. lit- .8 m rix and the body-lwfl including the fill nstuhe reasonable.

In Fig. 8 the filling tube that, ispnthc-matrix is designated31i and.isegenerally. rust -isq. l in shape with .theilarger diameter cndcqnne with the matrix The discharge, t b? $2 1? on the filling device isgcomplem ni a ing tube '3.I..so as to receive-the la t 3 th. its. inner sides in tigh enga ement withtm .Q tel': sides oftube cl. This stru tureis ;.suitah1 the larger diameter end ofrthefi zling lillk fi larger than-the openeside oizthecavit and Wax or compound thatnextends -QYfi '-:thQ-: Pfl= .Z. W-illlhave more holdingstren ththah with. straight sides of tubes-12.,

In Fig. 9 a more compact filling device vided for them in Fig- In Fig. 9. the .cyl drical body 34 in which .thewplastic charge aha held is the same as in Fig.- exccpt that itidoce not havethe external groove 24-therein,.and-th discharge :tube35 maybe threaded imbibed-lead 36 of saidbody-dl. The cap 31. has a flange-.38.;atlts open end the: same asncapal'l, but :the said .captelescopically: fills over the body :34. The spring -clip.;3.9-=is1 much the sameasclipz of Fig. l EXQEDfithfltihB. hook ends as are adaptedto. snap overtheclosed end of body34.. I

Instead ofthe longerplunger oftEig. 1 awpiston M is reciprocably filled in body; whichpiston may have a head at :theend adiace'ntdhe head 36 of body, and the other end-formedwithan axially rearwardly. opening recess in which spring] 42 extends.

This spring isadapted tomeact between the piston head and .a member M also reciprocable within body 34. An adjustingscrewiiizthreadede. ly extending through the head 46-011 thecap, is adapted to regulate the tensionon springAlwhsnthe ends are .engaged ,overthe endcof the body. 34. Screw .5 may also. extend. through thenlOsed endo! the clip 39-andia locknutA'Lon said screw may not only :lockthe screw in-adjusted position, but also clamp theclipfifl tocapiil. By recessing member M ier-the -spring the overall length of the filling material may \beyarled as desired and foundmecessariz. g

The .capis removedin exactly :.the' same manener -as-in the case.- of R091) 17,. By: pressing the legs of .clip .39 toward each other :betweenfiange 38 andthe-closed-endefthe clip, the outer ends of said legs will spring apart. A vent may be in the head of cap 3'! the same as in cap I! to permit free escape of air from within the cap as it is slipped over the body 34.

I claim:

1. In apparatus for filling the cavity in a tooth with a setting plastic material, a matrix of thin sheet material adapted to be trimmed and shaped to fit over said cavity with marginal portions against the marginal portions of said tooth around the edges of said cavity, an inlet in said matrix and a passageway communicating with said inlet through which said plastic material in a plastic state is adapted to be forced for ejection into said cavity when said matrix is secured over the latter, and means connected with said matrix for supplying'saicl material to said passageway for passage through the latter under pressure and means automatically operative for yieldably holding said material so injected into said cavity under uniform pressure during the setting period of said plastic.

2. In apparatus for filling the cavity in a tooth with a setting plastic material, a matrix ofthin sheet metal adapted to be trimmed and shaped to fit over said cavity and against said tooth, a cartridge for holding a supply of said material, a passageway communicating between the inside of said cartridge and the side of said matrix that is adapted to fit against said tooth for passage of said material from said cartridge into said cavity when said matrix is secured against said tooth, and means carried by said cartridge for moving said material through said passageway and means automatically operative for yieldably holding such material in said passageway and cavity under uniform pressure when said cavity is filled with material discharged from said passageway and when said matrix is secured against said tooth.

3. In apparatus for filling the cavity in a tooth with a setting plastic material, a matrix of thin sheet metal adapted to be trimmed and shaped to fit over said cavity and against said tooth, a cartridge for holding a supply of said material, a passageway communicating between the inside of said cartridge and the side of said matrix that is adapted to fit against said tooth for passage of said material from said cartridge into said cavity when said matrix is secured against said tooth, and means carried by said cartridge for moving said material through said passageway and means automatically operative for yieldably holding such material in said passageway and cavity under uniform pressure when said cavity is filled with material discharged from said passageway and when said matrix is secured against said tooth, said matrix being separable from said cartridge, and a quick detachable coupling releasably securing said matrix and said cartridge together.

4. An apparatus of the character described comprising: a cartridge holding a supply of a setting plastic material, a discharge outlet at one end of said cartridge adapted to be connected with the filling tube on a matrix, a piston within said cartridge movable toward said outlet and against such material when said cartridge has a charge of such material therein between said outlet and said piston, means for yieldably hold-' ing said piston against said plastic comprising a spring engaging the end of said piston opposite said plastic and an element releasably connected with a fixed point on said cartridge and said spring for holding said spring under compression against said piston.

5. An apparatus of the character described comprising: a cartridge holding a supply of a setting plastic material, a discharge outlet at one end of said cartridge adapted to be connected with the filling tube on a matrix, a piston within said cartridge movable toward said outlet and against such material when said cartridge has a charge of such material therein between said outlet and said piston, means for yieldably holding said piston against said plastic comprising a spring engaging the end of said piston opposite said plastic, spring arms releasably connected With said cartridge at opposite points thereon at one of their ends and a cross member connected with the opposite ends of said arms and over said spring for holding said spring under compression against said piston, said first mentioned ends being movable apart against their tension for release from said cartridge at said points.

6. In combination, a dental matrix having a filling tube projecting therefrom, a cartridge containing a supply of setting plastic filling material supported on said matrix and connected with said tube for discharge of said filling material through the latter, said cartridge being sufiiciently small and light and to be capable of being supported by said matrix and the tooth to be filled independently of manual or other support when said matrix is secured to said tooth, means carried by said cartridge for yieldably urging said supply of plastic material therefrom and through said tube for ejection into the cavity adapted to be covered by said matrix, said means including a spring and a member for releasably holding said spring under tension against said supply of plas- HILLARD M. HOLMES.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 571,965 Barker Nov. 24, 1896 712,526 Hammersmith Nov. 4, 1902 2,099,454 Siqveland Nov. 16, 1937 2,475,939 Applezweig July 12, 1949 OTHER REFERENCES Siqveland: Wax Patterns-a New Technique, Dental Survey, Nov. 1935, pp. 37-39.

, .Taking Impressions of Cavities Under Gum Margin, Siqveland, Dental Survey, December 1935, page 30. 

